check: more strict RDNS-Checking
check: more strict RDNS-Checking

The check did miss an error in jenas file: 117.10.in-addr.arpa as RDNS for net 10.17.0.0/16. This changes makes check detect that sort of error.

See icvpn-meta/#284

Ranlvor/icvpn-scripts,Ranlvor/icvpn-scripts